Etchant, display device and method for manufacturing display device using the same

ABSTRACT

An etchant includes: 5 to 20 wt % of persulfate, 1 to 10 wt % of at least one compound of an inorganic acid, an inorganic acid salt, or a mixture thereof, 0.3 to 5 wt % of a cyclic amine compound, 1 to 10 wt % of at least one compound of an organic acid, an organic acid salt, or a mixture thereof, 0.1 to 5 wt % of p-toluenesulfonic acid, and water, based on the total weight of the etchant. A copper-titanium etchant further includes 0.01 to 2 wt % of a fluoride-containing compound. A method of forming a display device using the etchant, and a display device, are also disclosed.

This application is a divisional of U.S. patent application Ser. No.13/168,408, filed on Jun. 24, 2011, which claims priority to KoreanPatent Application No. 10-2010-0128314 filed on Dec. 15, 2010, and allthe benefits accruing therefrom under 35 U.S.C. 119, the contents ofwhich in their entirety are herein incorporated by reference.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to an etchant, a display device using thesame and a method for manufacturing the display device.

(2) Description of the Related Art

In general, thin film transistor (“TFT”) array panels are used as acircuit board for independently driving each pixel in liquid crystaldisplays, organic electro luminescence (“EL”) display devices, etc. Thethin film transistor array panel has a scanning signal wire thattransfers a scanning signal on a gate wire, and an image signal linethat transfers an image signal on a data wire, and further includes athin film transistor that is connected to the gate wire and the datawire, and a pixel electrode that is connected to the thin filmtransistor.

Upon manufacturing the thin film transistor array panel, metal layersfor forming the gate wire and the data wire are stacked on a substrateand separated by insulating layers, followed by one or more processes ofetching the metal layers to form the gate wire and data wire.

Copper having high electrical conductivity and a low resistance may beused for the gate wire and the data wire. Increasing the size of displaydevices also increases the thickness of the copper wiring, which in turnmay cause a deterioration of profile in the thick copper wiring duringthe etching process.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

BRIEF SUMMARY OF THE INVENTION

In an embodiment, an etchant is provided, having an advantage of showingimproved etching characteristics during an etching process to form thickcopper wiring.

Also in an embodiment, a method is provided for manufacturing a displaydevice using the etchant.

An exemplary embodiment provides an etchant including: 5 to 20 wt % ofpersulfate, 1 to 10 wt % of at least one compound of an inorganic acid,an inorganic acid salt or a mixture comprising at least one of theforegoing, 0.3 to 5 wt % of a cyclic amine compound, 1 to 10 wt % of atleast one compound of an organic acid, an organic acid salt, or amixture comprising at least one of the foregoing, 0.1 to 5 wt % ofp-toluenesulfonic acid, and water, based on the total weight of theetchant.

The persulfate may include a compound selected from ammonium persulfate,sodium persulfate, potassium persulfate, or a combination comprising atleast one of the foregoing.

The inorganic acid may include a compound selected from nitric acid,sulfuric acid, phosphoric acid, perchloric acid, or a combinationcomprising at least one of the foregoing, and the inorganic acid saltmay include a compound selected from nitrate, sulfate, phosphate,perchlorate, or a combination comprising at least one of the foregoing.

The cyclic amine compound may include a compound selected from5-aminotetrazole, tolyltriazole, benzotriazole, methyltriazole, or acombination comprising at least one of the foregoing.

The organic acid may include a compound selected from acetic acid,glycolic acid, citric acid, oxalic acid, or a combination comprising atleast one of the foregoing, and the organic acid salt may include acompound selected from a potassium salt, a sodium salt, an ammoniumsalt, or a combination comprising at least one of the foregoing salts ofa compound selected from acetic acid, glycolic acid, citric acid, oxalicacid, or a combination comprising at least one of the foregoing acids.

The etchant may further include a fluoride-containing compound of 0.01to 2 wt % based on the total weight of the etchant.

The fluoride-containing compound may include a compound selected fromammonium fluoride, sodium fluoride, potassium fluoride, ammoniumbifluoride, sodium bifluoride, potassium bifluoride, or a combinationcomprising at least one of the foregoing.

Another exemplary embodiment provides a method for manufacturing adisplay device, including: forming a gate metal layer that includes alower gate metal layer on an insulation substrate, and an upper gatemetal layer on the lower gate metal layer; etching the gate metal layerusing a copper-titanium etchant to form a gate line including a gateelectrode; forming a gate insulating layer on the gate line;sequentially forming a first amorphous silicon layer on the gateinsulating layer, a second amorphous silicon layer on the firstamorphous silicon layer, a lower data metal layer on the secondamorphous layer, and an upper data metal layer on the lower data metallayer; etching the first amorphous silicon layer, the second amorphoussilicon layer, the lower data metal layer and the top data metal layerto form a semiconductor layer, an ohmic contact layer, a data lineincluding a source electrode and a drain electrode; forming apassivation layer on the data line, the drain electrode and the gateinsulating layer; and forming a pixel electrode electrically connectedto the drain electrode on the passivation layer, wherein thecopper-titanium etchant comprises 5 to 20 wt % of persulfate, 1 to 10 wt% of at least one compound of an inorganic acid, an inorganic acid salt,or a mixture comprising at least one of the foregoing, 0.3 to 5 wt % ofa cyclic amine compound, 1 to 10 wt % of at least one compound of anorganic acid, an organic acid salt, or a mixture comprising at least oneof the foregoing, 0.1 to 5 wt % of p-toluenesulfonic acid, 0.01 to 2 wt% of a fluoride-containing compound and water, based on the total weightof the etchant.

The lower gate metal layer and the lower data metal layer may be made oftitanium or a titanium-containing metal, and the upper gate metal layerand the upper data metal layer may be made of copper orcopper-containing metal.

The upper data metal layer and the lower data metal layer may be etchedusing the copper-titanium etchant at the same time.

In an alternative embodiment, the upper data metal layer may be etchedusing a copper etchant.

The copper etchant may comprise 5 to 20 wt % of persulfate, 1 to 10 wt %of at least one compound of an inorganic acid, an inorganic acid salt,or a mixture comprising at least one of the foregoing, 0.3 to 5 wt % ofa cyclic amine compound, 1 to 10 wt % of at least one compound of anorganic acid, an organic acid salt, or a mixture comprising at least oneof the foregoing, 0.1 to 5 wt % of p-toluenesulfonic acid and water,based on the total weight of the etchant.

Yet another exemplary embodiment provides a display device including: aninsulation substrate, a gate line disposed on the insulation substrate,a gate insulating layer disposed on the gate line, a semiconductor layerdisposed on the gate line, a data line disposed on the semiconductorlayer and including a source electrode electrically connected to thedata line, a drain electrode disposed on the semiconductor layer on asame surface as and facing the source electrode, and a pixel electrodeelectrically connected to the drain electrode, wherein the gate line,the data line and the drain electrode each include a lower layer made oftitanium or titanium-containing metal and an upper layer disposed on thelower layer and made of copper or copper-containing metal, respectively,and the upper layer has a thickness of 10,000 to 50,000 Å and a lateralside of the upper layer is inclined to the insulation substrate by anangle of 40 to 60 degrees.

According to exemplary embodiments, etching characteristics of a thickcopper layer can be improved by using the copper-titanium etchant or thecopper etchant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a layout view of a thin film transistor array panel accordingto an exemplary embodiment.

FIG. 2 is a cross-sectional view taken along line II-II′ of FIG. 1.

FIG. 3 to FIG. 8 are cross-sectional views sequentially illustrating amethod for manufacturing a thin film transistor array panel for adisplay device according to an exemplary embodiment.

FIG. 9 is a cross-sectional view illustrating a part of a manufacturingmethod of a thin film transistor array panel for a display deviceaccording to an exemplary embodiment.

Description of symbols in the Figures 110: Substrate 121: Gate line 154:Semiconductor layer 171: Data line 173: Source electrode 175: Drainelectrode

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As those skilled in the art would realize,the described embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, regions, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, regions, integers, steps,operations, elements, components, and/or groups thereof. All ranges andendpoints reciting the same feature are independently combinable.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element orintervening elements may also be present. In contrast, when an elementis referred to as being “directly on” another element, there are nointervening elements present.

Hereinafter, an etchant according to an exemplary embodiment will bedescribed.

An etchant according to an exemplary embodiment includes acopper-titanium etchant capable of simultaneous, sequential etching of adouble layer (e.g., of a copper layer and a titanium layersimultaneously, or a copper layer followed by a titanium layer later inthe same etch process), and a copper etchant capable of selectivelyetching copper (Cu) or a copper-containing metal layer, in which theetchant is used for etching a metal wiring of a double layer having atitanium (Ti) or titanium-containing metal layer and a copper (Cu) orcopper-containing metal layer formed on the titanium (Ti) ortitanium-containing metal layer.

Copper-Titanium Etchant

First, the copper-titanium etchant will be described in detail.

The copper-titanium etchant according to the exemplary embodimentincludes persulfate; a fluoride-containing compound; at least onecompound of an inorganic acid, an inorganic acid salt, or a mixturecomprising at least one of the foregoing; a cyclic amine compound; atleast one compound of an organic acid, an organic acid salt, or amixture comprising at least one of the foregoing; p-toluenesulfonicacid; and water.

The persulfate is the primary oxidizing agent for etching the copper orcopper-containing metal layer, and is included in an amount of 5 to 20wt %, and preferably 7 to 18 wt %, based on the total weight of thecopper-titanium etchant. The persulfate included in the copper-titaniumetchant in this amount allows for the copper or copper-containing metallayer to be etched in an appropriate manner, and so that the etchingprofile is improved.

The persulfate may be selected from ammonium persulfate (“APS”), sodiumpersulfate (“SPS”), potassium persulfate (“PPS”), or a combinationcomprising at least one of the foregoing.

The fluoride-containing compound is a primary ingredient for etching thetitanium or titanium-containing metal layer, and is included in anamount of 0.01 to 2 wt %, and preferably 0.05 to 1 wt %, based on thetotal weight of the copper-titanium etchant. The fluoride-containingcompound included in the copper-titanium etchant in this amount allowsfor the titanium or titanium-containing metal layer to be etched in anappropriate manner, and so that the etching profile is improved.

If the content of the fluoride-containing compound is less than 0.01 wt%, the etching speed of the titanium or titanium-containing metal layermay deteriorate (e.g., by steadily slowing), leading to formation ofetching residues. If the content of the fluoride-containing compound ismore than 2 wt %, a substrate having copper or titanium copper on it,such as glass or a silicon-containing insulating layer, may be damaged.

The fluoride-containing compound is a compound that is able todissociate into fluoride ion or polyatomic fluoride ion, and may beselected from ammonium fluoride, sodium fluoride, potassium fluoride,ammonium bifluoride, sodium bifluoride, potassium bifluoride, and acombination comprising at least one of the foregoing.

At least one compound of an inorganic acid, an inorganic acid salt, or amixture comprising at least one of the foregoing oxidizes and etches thecopper or copper-containing metal layer, and oxidizes the titanium ortitanium-containing metal layer.

At least one compound of an inorganic acid, an inorganic acid salt, or amixture comprising at least one of the foregoing is included in anamount of 1 to 10 wt %, and preferably 2 to 7 wt %, based on the totalweight of the copper-titanium etchant.

At least one compound of an inorganic acid, an inorganic acid salt, or amixture comprising at least one of the foregoing, included in thecopper-titanium etchant in this amount allows the copper orcopper-containing metal layer and the titanium or titanium-containingmetal layer to be etched in an appropriate manner, and so that theetching profile is improved.

If the content of at least one compound of an inorganic acid, aninorganic acid salt, or a mixture comprising at least one of theforegoing is less than 1 wt %, the etching speed may deteriorate,generating etching profile defects and forming etching residues. If thecontent of at least one compound of an inorganic acid, an inorganic acidsalt, a mixture comprising at least one of the foregoing is 10 wt % ormore, over-etching may occur, which can in turn cause cracks in thephotoresist pattern adjacent to and defining the area being etched;etchant which penetrates the cracks may short or otherwise damage thewiring formed by the etching.

The inorganic acid may be selected from nitric acid, sulfuric acid,phosphoric acid, perchloric acid, or a combination comprising at leastone of the foregoing, and the inorganic acid salt may be selected fromnitrate, sulfate, phosphate and perchlorate, or a combination comprisingat least one of the foregoing anions. The inorganic acid salt mayinclude as a cation an alkali metal cation including a lithium, sodium,or potassium cation; an ammonium cation, an alkaline earth metal cationincluding magnesium or calcium cation; or a combination comprising atleast one of the foregoing cations.

The cyclic amine compound, included in the etchant, controls theformation of a profile upon etching the copper or copper-containingmetal layer. The cyclic amine compound is included in an amount of 0.3to 5 wt %, and preferably 0.5 to 3 wt %, based on the total weight ofthe copper-titanium etchant. The cyclic amine compound. included in thecopper-titanium etchant in this amount allows for a suitable copperetching rate and formation of a suitable taper angle for the sidewall ofthe etched wiring, and the amount of lateral etching can be controlled.

The cyclic amine compound is a C₂₋₂₀ triazole and may be selected from5-aminotetrazole, tolytriazole, benzotriazole, methyltriazole, or acombination comprising at least one of the foregoing.

At least one compound of an organic acid, an organic acid salt, or amixture comprising at least one of the foregoing further controls thetaper angle of copper or copper-containing metal layer and the etchingspeed of the copper or copper-containing metal layer, to maintain apredetermined etching profile for a desirable lateral etching.

At least one compound of an organic acid. an organic acid salt, or amixture comprising at least one of the foregoing is included in anamount of 1 to 10 wt %, and preferably 2 to 7 wt %, based on the totalweight of the copper-titanium etchant.

If the content of at least one compound of an organic acid, an organicacid salt, or a mixture comprising at least one of the foregoing is lessthan 1 wt %, it is difficult to consistently maintain a predeterminedetching profile. If the content of at least one compound of an organicacid. an organic acid salt, a mixture comprising at least one of theforegoing is 10 wt % or more, over-etching may occur to increase thelateral etching.

The organic acid may be a C₁₋₂₀ carboxylic acid selected from aceticacid, glycolic acid, citric acid, oxalic acid, or a combinationcomprising at least one of the foregoing, and the organic acid salt maybe selected from a potassium salt, a sodium salt, an ammonium salt or acombination comprising at least one of the foregoing of a compoundselected from acetic acid, glycolic acid, citric acid, oxalic acid, or acombination comprising at least one of the foregoing.

The inclusion of p-toluenesulfonic acid in the etchant as a stabilizerprevents changes in the etching characteristics due to secular changesoccurring in the composition after preparation of the copper-titaniumetchant, and allows for long term storage of the copper-titanium etchantby improving shelf-life, relative to comparable but unstabilized etchantcompositions.

The p-toluenesulfonic acid is included in an amount of 0.1 to 5 wt %,and preferably 0.5 to 3 wt %, based on the total weight of thecopper-titanium etchant.

If the content of p-toluenesulfonic acid is less than 0.1 wt %, changesin the etchant due to secular changes (i.e., degradation of thecomposition and loss of efficacy upon standing) may occur. If thecontent of p-toluenesulfonic acid is equal to or more than 3 wt %, thesecular changes can be prevented, but over-etching due to theaccompanying increased acidity may cause deterioration of the profile ofthe wiring.

Water is deionized water, and water used in semiconductor processing isused, and water of 18 milliohm per centimeter (MSΩ/cm) or lower ispreferred. Water is included with the etchant components in thecopper-titanium etchant to provide the compositional balance of 100 wt%, based on the total weight of the copper-titanium etchant.

In addition to the aforementioned etchant components, thecopper-titanium etchant may further include at least one ingredientselected from an etching adjustment agent, a surfactant, a chelatingagent, a corrosion inhibitor, or a combination comprising at least oneof the foregoing, where it will be understood that inclusion of suchfurther ingredients will displace a corresponding weight percentage ofwater.

The copper-titanium etchant effectively etches a double layer having thetitanium or titanium-containing metal layer and the copper orcopper-containing metal layer formed on the titanium ortitanium-containing metal layer, to provide the metal wiring withdesirable profile and low or no defectivity.

Hereinafter, performance of the copper-titanium etchant of will bedescribed with reference to specific Experimental Examples.

Example 1

As shown in Table 1, 180 kg of a copper-titanium etchant that contains10 wt % of ammonium persulfate, 0.5 wt % of ammonium bifluoride, 3 wt %of nitric acid, 1 wt % of 5-aminotetrazole, 3 wt % of ammonium acetate,5 wt % of acetic acid, 2 wt % of p-toluenesulfonic acid and water wasprepared.

Comparative Example 1

As shown in Table 1, 180 kg of a copper-titanium etchant that contains10 wt % of ammonium persulfate, 0.5 wt % of ammonium bifluoride, 3 wt %of nitric acid, 1 wt % of 5-aminotetrazole and water was prepared.

TABLE 1 APS ABF HNO₃ ATZ AA AcOH PTA water (wt %) (wt %) (wt %) (wt %)(wt %) (wt %) (wt %) (wt %) Example 1 10 0.5 3 1 3 5 2 Residual amountComparative 10 0.5 3 1 0 0 0 Residual Example 1 amount APS: Ammoniumpersulfate ABF: Ammonium bifluoride ATZ: 5-aminotetrazole AA: Ammoniumacetate AcOH: Acetic acid PTA: p-toluenesulfonic acid

Experimental Example 1 Evaluation of Etching Characteristics

A SiNx layer is deposited on a glass substrate by PECVD, a titaniumlayer having a thickness of 300 angstrom (Å) is laminated onto the SiNxlayer, and a copper layer having a thickness of 15000 angstrom (Å) islaminated on the titanium layer. A photoresist was applied to the coppersurface and patterned, and the substrate having the predeterminedphotoresist pattern on the copper layer was cut using a diamond blade toprepare samples of 550×650 mm.

The copper-titanium etchants of Example 1 and Comparative Example 1 wereloaded into a spray type etching test apparatus, and heated to atemperature in excess of 25° C. Thereafter, when the etchant temperaturereached 30±0.1° C., an etching process was performed to form wiringfeatures. A total etching time was performed to achieve 40% of thestandard for end-point detection (“EPD”). The sample was loaded, and thespray etching was performed. When the etching to open the wiring testfeatures was completed, the sample was removed from the apparatus andthen washed with deionized water and dried by using a hot forced-airdrying device. The residual photoresist was removed with a solvent-basedphotoresist stripper. After subsequent washing and drying, a scanningelectron microscope (“SEM”) was used to evaluate etching characteristicsbased on analysis of the profile and critical dimensions of the etchedwiring features. The results are shown in Table 2.

Experimental Example 2 Evaluation of Storage Characteristics

The copper-titanium etchants of Example 1 and Comparative Example 1 wereprepared in a quantity sufficient to perform a reference etch, and theremaining etchant for each was stored at 25° C. for a scheduled storagetest date of 5 days. After the scheduled date, an etching test was againperformed using the aged etchants of Example 1 and Comparative Example 1under the same conditions used for the reference etch. The results werethen compared with the reference etch test results. The results areshown in Table 2.

Experimental Example 3 Evaluation of Number of Processing Sheets

A reference etch was performed using the copper-titanium etchants ofExample 1 and Comparative Example 1, and 4,000 ppm of copper powder wasadded and dissolved completely, to simulate the amount of copper presentin the etchant after processing an arbitrary number of sheets. A secondetch test was subsequently performed using the etchant containing thedissolved copper to approximate a useful lifetime of the etchant. Wherethe difference in the amount of lateral etching compared to that ofreference test exceeded 0.2 μm, the etched sample was classified asbeing defective, indicative that the etchant had exceeded its usefullifetime for the number of sheets of copper-titanium clad substratesprocessable using the etchant (i.e., “processing sheets”). The resultsare shown in Table 2.

TABLE 2 Number of processing sheets (difference in Etching Storagelateral etch between charac- charac- reference and second teristicsteristics etch test) Example 1 CD Skew: ≦1 μm, Etching Difference inTaper angle: 40 to profile: lateral etch 60 degrees excellent Within 0.2μm Compar- CD Skew: ≦1 μm, Etching Difference in ative Taper angle: 40to profile: ≦good lateral etch Example 1 60 degrees Exceeding 0.2 μm

Referring to Table 2, the copper-titanium etchant according to Example 1showed excellent etching characteristics including a critical dimension(“CD”) Skew of ≦1 μm and a taper angle of 40 to 60 degrees of thesidewall relative to the plane of the substrate, and also excellentstorage characteristics and number of processing sheets.

The copper-titanium etchant of Comparative Example 1 which contains noorganic acid salt and p-toluenesulfonic acid also showed desirableetching characteristics including a CD Skew of ≦1 μm and a taper angleof 40 to 60 degrees comparable to that of Example 1, but exhibited poorstorage characteristics and a low theoretical number of processingsheets relative to Example 1.

Copper Etchant

Subsequently, a copper etchant capable of selectively etching a copperor copper-containing metal in the metal wiring that is formed of adouble layer having a titanium or titanium-containing metal layer and acopper or copper-containing metal layer formed on the titanium ortitanium-containing metal layer will be described.

The copper etchant according to an Example of the present inventionincludes persulfate; at least one compound of an inorganic acid, aninorganic acid salt, or a mixture comprising at least one of theforegoing; a cyclic amine compound; at least one compound of an organicacid, an organic acid salt, or a mixture comprising at least one of theforegoing; p-toluenesulfonic acid; and water.

That is, the copper etchant according to the Example does not include afluoride-containing compound, in contrast to the copper-titaniumetchant. Including a fluoride-containing compound in the copper etchantwould damage titanium or titanium-containing metal layer.

The persulfate is the primary oxidizing agent for etching the copper orcopper-containing metal layer, and is included in an amount of 5 to 20wt %, and preferably 7 to 18 wt %, based on the total weight of thecopper etchant. The persulfate included in the copper etchant in thisamount allows for the copper or copper-containing metal layer to beetched in an appropriate manner so that the etching profile is improved.

The persulfate may be selected from ammonium persulfate (APS), sodiumpersulfate (SPS), potassium persulfate (PPS) or a combination comprisingat least one of the foregoing.

At least one compound of an inorganic acid, an inorganic acid salt, or amixture comprising at least one of the foregoing oxidizes and etches thecopper or copper-containing metal layer.

At least one compound of an inorganic acid, an inorganic acid salt, or amixture comprising at least one of the foregoing is included in anamount of 1 to 10 wt %, and preferably 2 to 7 wt %, based on the totalweight of the copper etchant. At least one compound of an inorganicacid, an inorganic acid salt, a mixture comprising at least one of theforegoing, included in the copper etchant in this amount allows thecopper or copper-containing metal layer to be etched in an appropriatemanner, and so that the etching profile is improved.

If the content of at least one compound of an inorganic acid, aninorganic acid salt, or a mixture comprising at least one of theforegoing is less than 1 wt %, the etching speed may deteriorate,generating etching profile defects and forming etching residues. If thecontent of at least one compound of an inorganic acid, an inorganic acidsalt, or a mixture comprising at least one of the foregoing is equal toor more than 10 wt %, over-etching may occur, which can in turn causecracks in the photoresist pattern adjacent to and defining the areabeing etched; etchant which penetrates the cracks may short or otherwisedamage the wiring formed by the etching.

The inorganic acid may be selected from nitric acid, sulfuric acid,phosphoric acid, perchloric acid, or a combination comprising at leastone of the foregoing, and the inorganic acid salt may be selected fromnitrate, sulfate, phosphate, perchlorate, or a combination comprising atleast one of the foregoing anions. The inorganic acid salt may includeas a cation an alkali metal cation including a lithium, sodium, orpotassium cation; an ammonium cation, an alkaline earth metal cationincluding magnesium or calcium cation; or a combination comprising atleast one of the foregoing cations.

The cyclic amine compound, included in the etchant, controls theformation of a profile upon etching the copper or copper-containingmetal layer. The cyclic amine compound is included in an amount of 0.3to 5 wt %, and preferably 0.5 to 3 wt %, based on the total weight ofthe copper etchant. The cyclic amine compound, included in the copperetchant in this amount allows for a suitable copper etching rate andformation of a suitable taper angle for the sidewall of the etchedwiring, and the amount of lateral etching can be controlled.

The cyclic amine compound is a C₂₋₂₀ triazole and may be selected from5-aminotetrazole, tolytriazole, benzotriazole, methyltriazole, or acombination comprising at least one of the foregoing.

At least one compound of an organic acid, an organic acid salt, or amixture comprising at least one of the foregoing further controls thetaper angle of copper or copper-containing metal layer and the etchingspeed of the copper or copper-containing metal layer to maintain apredetermined etching profile for a desirable lateral etching.

At least one compound of an organic acid, an organic acid salt, amixture comprising at least one of the foregoing is included in anamount of 1 to 10 wt %, and preferably 2 to 7 wt %, based on the totalweight of the copper etchant.

If the content of at least one compound of an organic acid, an organicacid salt, or a mixture comprising at least one of the foregoing is lessthan 1 wt %, it is difficult to consistently maintain a predeterminedetching profile. If the content of at least one compound of an organicacid, an organic acid salt, or a mixture comprising at least one of theforegoing is 10 wt % or more, over-etching may occur to increase thelateral etching.

The organic acid may be a C₁₋₂₀ carboxylic acid selected from aceticacid, glycolic acid, citric acid, oxalic acid, or a combinationcomprising at least one of the foregoing, and the organic acid salt maybe selected from a potassium salt, a sodium salt an ammonium salt, or acombination comprising at least one of the foregoing of a compoundselected from acetic acid, glycolic acid, citric acid, oxalic acid or acombination comprising at least one of the foregoing.

The inclusion of p-toluenesulfonic acid in the etchant as a stabilizerprevents changes in the etching characteristics due to secular changesoccurring in the composition after preparation of the copper etchant,and allows for long term storage of the copper etchant by improvingshelf-life, relative to comparable but unstabilized etchantcompositions.

The p-toluenesulfonic acid is included in an amount of 0.1 to 5 wt %,and preferably 0.5 to 3 wt %, based on the total weight of the copperetchant.

If the content of p-toluenesulfonic acid is less than 0.1 wt %, changesin the etchant due to secular changes (i.e., degradation of thecomposition and loss of efficacy upon standing) may occur. If thecontent of p-toluenesulfonic acid is 3 wt % or more, the secular changescan be prevented, but over-etching due to the accompanying increasedacidity may cause deterioration of the profile of the wiring.

Water is deionized water, and water used in semiconductor processing isused, and water of 18 milliohm per centimeter (MSΩ/cm) or lower ispreferred. Water is included with the etchant components in the copperetchant to fill up to provide the compositional balance of 100 wt %,based on the total weight of the copper etchant.

In addition to the aforementioned etchant components, the copper etchantmay further include at least one ingredient selected from an etchingadjustment agent, a surfactant, a chelating agent, a corrosioninhibitor, or a combination comprising at least one of the foregoing,where it will be understood that inclusion of such further ingredientswill displace a corresponding weight percentage of water.

The copper etchant effectively and selectively etches a copper orcopper-containing metal in the metal wiring, including a copper orcopper-containing layer of a double layer having a titanium ortitanium-containing metal layer and a copper or copper-containing metallayer formed on the titanium or titanium-containing metal layer. Thecopper etchant, prepared using components in the above components, doesnot damage the titanium or titanium-containing metal layer.

Hereinafter, performance of the copper etchant will be described withreference to specific Experimental Examples.

Example 2

As shown in the following Table 3, 180 kg of a copper etchant thatcontains 12 wt % of ammonium persulfate, 3 wt % of nitric acid, 0.5 wt %of 5-aminotetrazole, 2 wt % of ammonium acetate, 5 wt % of acetic acid,1 wt % of p-toluenesulfonic acid and water was prepared.

Comparative Example 2

As shown in the following Table 3, 180 kg of a copper etchant thatcontains 10 wt % of ammonium persulfate, 3 wt % of nitric acid, 0.5 wt %of 5-aminotetrazole and water was prepared.

Comparative Example 3

As shown in the following Table 3, 180 kg of a copper etchant thatcontains 12 wt % of ammonium persulfate, 3 wt % of nitric acid, 0.5 wt %of 5-aminotetrazole, 2 wt % of ammonium acetate, 5 wt % of acetic acid,1 wt % of p-toluenesulfonic acid, 0.05 wt % of ammonium fluoride andwater was prepared.

TABLE 3 APS HNO₃ ATZ AA AcOH PTA AF Water (wt %) (wt %) (wt %) (wt %)(wt %) (wt %) (wt %) (wt %) Example 2 12 3 0.5 2 5 1 0 Residual amountComparative 12 3 0.5 0 0 0 0 Residual Example 2 amount Comparative 12 30.5 2 5 1 0.05 Residual Example 3 amount APS: Ammonium persulfate ATZ:5-aminotetrazole AA: Ammonium acetate AcOH: Acetic acid PTA:p-toluenesulfonic acid AF: Ammonium fluoride

Experimental Example 4 Evaluation of Etching Characteristics

A SiNx layer is deposited on a glass substrate by PECVD, a titaniumlayer having a thickness of 300 angstrom (Å) is laminated onto the SiNxlayer, and a copper layer having a thickness of 20000 angstrom (Å) islaminated on the titanium layer. A photoresist was applied to the coppersurface and patterned, and the substrate having the predeterminedphotoresist pattern on the copper layer was cut using a diamond blade toprepare samples of 550×650 mm.

The copper etchants of Example 2, Comparative Example 2 and ComparativeExample 3 were loaded into a spray type etching test apparatus, andheated to a temperature in excess of 25° C. Thereafter, when thetemperature reached 30±0.1° C., an etching process was performed to formwiring features. A total etching time was performed to achieve 40% ofthe standard for end-point detection (EPD). The sample was loaded, andthe spray etching was performed. When the etching to open the wiringtest features was completed, the sample was removed from the apparatusand then washed with deionized water and dried by using a hot forced-airdrying device. The residual photoresist was removed with a solvent-basedphotoresist stripper. After subsequent washing and drying, a scanningelectron microscope (SEM) was used to evaluate etching characteristicsbased on analysis of the profile and critical dimensions of the etchedwiring features. The results are shown in Table 4.

Experimental Example 5 Evaluation of Storage Characteristics

The copper etchants of Example 2 and Comparative Example 2 were preparedin a quantity sufficient to perform a reference etch, and the remainingetchant for each was stored at 25° C. for a scheduled storage test dateof 5 days, and after the scheduled date, an etching test was againperformed using the aged etchants of Example 2 and Comparative Example 2under the same conditions used for the reference etch (carried outbefore storage of the etchant). The results were then compared with thereference etch test results. The results are shown in Table 4.

Experimental Example 6 Evaluation of Number of Processing Sheets

A reference etch was performed using the copper etchants of Example 2and Comparative Example 2, and 4,000 ppm of copper powder was added anddissolved completely to simulate the amount of copper present in theetchant after processing an arbitrary number of sheets. A second etchtest was subsequently performed using the etchant containing thedissolved copper to approximate a useful lifetime of the etchant. Wherethe difference in the amount of lateral etching compared to that ofreference test exceeded 0.2 μm, the etched sample was classified asdefective, indicative that the etchant had exceeded its useful lifetimefor the number of sheets of copper-titanium clad substrates processableusing the etchant (i.e., “processing sheets”). The results are shown inTable 4.

TABLE 4 Number of processing sheets (difference in Etching Storagelateral etch between charac- charac- reference and second teristicsteristics etch test) exemplary CD Skew: ≦1 μm, Etching Difference inembodi- Taper angle: 40 to profile: lateral etch ment2 60 degreesexcellent Within 0.2 μm Compar- CD Skew: ≦1 μm, Etching Difference inative Taper angle: 40 to profile: ≦good lateral etch Example2 60 degreesExceeding 0.2 μm Compar- lower layer — — ative (Ti) damage Example3

Referring to Table 4, the copper etchant according to Example 2 showedvery excellent etching characteristics including a critical dimension(CD) Skew of ≦1 μm and taper angle of 40 to 60 degrees of the sidewallrelative to the plane of the substrate, and also excellent storagecharacteristics and number of processing sheets.

Meanwhile, the copper etchant of Comparative Example 2 which contains noorganic acid salt and p-toluenesulfonic acid also showed desirableetching characteristics including a CD Skew of ≦1 μm and a taper angleof 40 to 60 degrees comparable to that of Example 2, but exhibited poorstorage characteristics and a low number of processing sheets relativeto Example 2.

In addition, the copper etchant of Comparative Example 3 which isprepared by addition of ammonium fluoride to the copper etchant ofExample 2 caused damage to the titanium layer.

The copper-titanium etchant and copper etchant according to the aboveExamples can be used in the fabrication of a memory semiconductordisplay panel as well as a flat panel display such as a liquid crystaldisplay. In addition, these etchants can be used in the fabrication ofother electronic devices such as those including metal wiring formed ofa double layer having a titanium or titanium-containing metal layer anda copper or copper-containing metal layer formed on the titanium ortitanium-containing metal layer.

Display Device

Hereinafter, a method of manufacturing a display device using the abovedescribed copper-titanium etchant and copper etchant according to theabove Examples will be described.

FIG. 1 is a layout view of a thin film transistor array panel accordingto an exemplary embodiment, and FIG. 2 is a cross-sectional view takenalong line II-II′ of FIG. 1.

In the thin film transistor array panel of a display device according toan exemplary embodiment, a plurality of gate lines 121 (FIG. 1)including a gate electrode 124 (FIG. 2) are formed on a surface of asubstrate 110 made of an insulating material such as glass or plastic,and (as seen in FIG. 2) a gate insulating layer 140, a plurality ofsemiconductor layers 154, a plurality of ohmic contacts 163 and 165, aplurality of data lines 171 and a plurality of drain electrodes 175 aresequentially formed thereon.

The gate line 121 transmits a gate signal and extends chiefly in ahorizontal direction, and the gate electrode 124 protrudes to upside ofthe gate line 121.

As shown in FIG. 2, the gate line 121 includes a lower layer 124 p madeof titanium or titanium-containing metal and disposed on a surface ofthe substrate 110, and an upper layer 124 r made of copper orcopper-containing metal, and disposed on a surface of and in contactwith the lower layer 124 p. Herein, the upper layer 124 r has athickness of 10,000 to 50,000 Å and a lateral side of the upper layer124 r is inclined toward the substrate 110 at an angle of preferably 40to 60 degrees.

The data line 171 transmits a data signal, and extends chiefly in avertical direction to insulatedly cross the gate line 121. Each dataline 171 includes a plurality of source electrodes 173 extending alongthe plane of the substrate 110 toward the gate electrode 124. The drainelectrode 175 is separated from the data line 171 and faces the sourceelectrode 173 in the plane of the substrate 110 with respect to the gateelectrode 124, as shown in FIG. 2.

The data line 171, the source electrode 173 and the drain electrode 175are composed of lower layers 171 p, 173 p, and 175 p made of titanium ortitanium-containing metal and disposed on a surface of semiconductorlayer 154 and upper layers 171 r, 173 r, and 175 r made of copper orcopper-containing metal. Herein, the upper layers 171 r, 173 r, and 175r each have a thickness of 10,000 to 50,000 Å, and a lateral side of theupper layer 124 r is inclined toward the substrate 110 and the angle ispreferably 40 to 60 degrees.

The semiconductor layer 154 is positioned on the gate electrode 124(with gate insulating layer 140 disposed between surfaces of theselayers 154 and 124), and the ohmic contacts 163 and 165 disposed on asurface of semiconductor layer 154 are only disposed between surfaces ofthe semiconductor layer 154 and the data line 171 and the drainelectrode 175 to reduce contact resistance therebetween.

A single gate electrode 124, and a single source electrode 173 and asingle drain electrode 175 each vertically and insulatedly overlappingthe single gate electrode 124 constitutes a single thin film transistortogether with the semiconductor layer 154, and a channel C of the thinfilm transistor is formed in the semiconductor layer 154 between thesource electrode 173 and the drain electrode 175.

A passivation layer 180, made of silicon nitride and/or silicon oxide,is formed on exposed surfaces of the data line 171 and the drainelectrode 175.

A contact hole 185, exposing the drain electrode 175 (specifically,layer 175 r), is formed in the passivation layer 180, and a pixelelectrode 191, connected to the drain electrode 175 via the contact hole185, is formed on a surface of the passivation layer 180.

Hereinafter, a method for manufacturing the thin film transistor arraypanel for a display device according to an exemplary embodiment will bedescribed with reference to FIGS. 3 to 9 and FIG. 2.

FIG. 3 to FIG. 8 are cross-sectional views sequentially illustrating amethod for manufacturing a thin film transistor array panel for adisplay device according to an exemplary embodiment.

First, as shown in FIG. 3, the gate metal layer 120 having a lower gatemetal layer 120 p made of titanium or titanium-containing metal isformed on a surface of the transparent insulation substrate 110, and anupper gate metal layer 120 r made of copper or copper-containing metalis formed on a surface of the lower gate metal layer 120 p.

Subsequently, as shown in FIG. 4, the gate metal layer 120 is patternedusing e.g., a photoresist pattern forming process, and etched using thecopper-titanium etchant according to the above described exemplaryembodiment so as to form the gate electrode 124, and the gate insulatinglayer 140 is formed on a surface of the insulation substrate 110(corresponding to the front, i.e., viewing, side of the display preparedby this method) to cover the surface of 110 and the gate electrode 124.

The gate electrode 124 has a lower layer 124 p made of titanium ortitanium-containing metal and an upper layer 124 r made of copper orcopper-containing metal. Herein, the upper layer 124 r has a thicknessof 10,000 to 50,000 Å, and a lateral side of the upper layer 124 r isinclined toward the substrate 110, at an angle of preferably 40 to 60degrees.

Subsequently, as shown in FIG. 5, an amorphous silicon layer 150 isdeposited on a surface of the gate insulating layer 140, an amorphoussilicon layer 160 doped with impurities (e.g., p-type dopants such asboron, aluminum, etc. or n-type dopants such as phosphorus, arsenic,antimony, etc.) is deposited on a surface of the amorphous silicon layer150, and a data metal layer 170 is deposited on a surface of the dopedamorphous silicon layer 160. Herein, the data metal layer 170 has alower data metal layer 170 p made of titanium or titanium-containingmetal and deposited on the surface of the doped amorphous silicon layer160, and an upper data metal layer 170 r made of copper orcopper-containing metal and deposited on a surface of the lower datametal layer 170 p.

Subsequently, as shown in FIG. 6 and FIG. 7, the data metal layer 170 ispatterned using e.g., a photoresist pattern forming process, and etchedusing the copper-titanium etchant according to the above describedexemplary embodiment (FIG. 6), and the amorphous silicon layer 150 andthe amorphous silicon layer 160 doped with impurities are etched to forma data line 171 including a source electrode 173, a drain electrode 175,ohmic contact layers 163 and 165 and a semiconductor layer 154, wherethe source electrode 173 and drain electrode 175 are formed by exposingafter etch a portion of the surface of semiconductor layer 154 to formchannel C (FIG. 7).

The data line 171, the source electrode 173 and the drain electrode 175include, respectively, lower layers 171 p, 173 p, and 175 p made oftitanium or titanium-containing metal, and upper layers 171 r, 173 r,and 175 r made of copper or copper-containing metal. Herein, the upperlayers 171 r, 173 r, and 175 r have a thickness of 10,000 to 50,000 Å,and the lateral sides of the upper layers 171 r, 173 r, and 175 r areinclined toward the side of the substrate 110, at an angle of preferably40 to 60 degrees.

Subsequently, as shown in FIG. 8, a passivation layer 180 is formed onthe surface (i.e., front side) including the data line 171, the drainelectrode 175 and the gate insulating layer 140, and then, as shown inFIG. 2, a contact hole 185 exposing the drain electrode 175 is formed inthe passivation layer 180 over drain electrode 175 to expose a portionof the surface of upper layer 175 r of the drain electrode 175, and apixel electrode 191 is formed on a surface of the passivation layer 180including the interior of contact hole 185 to contact the upper layer175 r of drain electrode 175.

In addition, as shown in FIG. 9, the upper data metal layer 170 r andthe lower data metal layer 170 p are not etched at the same time, butthe upper data metal layer 170 r may be etched first, and then the lowerdata metal layer 170 p may be etched second. Where it is desirable to doso, the upper data metal layer 170 r is etched using the copper etchantaccording to the above described exemplary embodiment without damagingto the lower data metal layer 170 p.

Subsequently, as shown in FIG. 7, the data line 171 including the sourceelectrode 173, the drain electrode 175, the ohmic contact layers 163 and165 and the semiconductor layer 154 are formed.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims. In the present exemplary embodiment, aliquid crystal display is exemplified, but the present invention may beapplied to a variety of other display devices including a thin filmtransistor.

What is claimed is:
 1. A method for manufacturing a display device,comprising: forming a gate metal layer that includes a lower gate metallayer on an insulation substrate, and an upper gate metal layer on thelower gate metal layer; etching the gate metal layer using acopper-titanium etchant to form a gate line including a gate electrode;forming a gate insulating layer on the gate line; sequentially forming afirst amorphous silicon layer on the gate insulating layer, a secondamorphous silicon layer on the first amorphous silicon layer, a lowerdata metal layer on the second amorphous silicon layer, and an upperdata metal layer on the lower data metal layer; etching the firstamorphous silicon layer, the second amorphous silicon layer, the lowerdata metal layer and the upper data metal layer to form a semiconductorlayer, an ohmic contact layer, a data line including a source electrode,and a drain electrode; forming a passivation layer on the data line, thedrain electrode and the gate insulating layer; and forming a pixelelectrode electrically connected to the drain electrode on thepassivation layer, wherein the copper-titanium etchant includes 5 to 20wt % of persulfate, 1 to 10 wt % of at least one compound of aninorganic acid, an inorganic acid salt, or a mixture comprising at leastone of the foregoing, 0.3 to 5 wt % of a cyclic amine compound, 1 to 10wt % of at least one compound of an organic acid, an organic acid salt,or a mixture comprising at least one of the foregoing, 0.1 to 5 wt % ofp-toluenesulfonic acid, 0.01 to 2 wt % of a fluoride-containingcompound, and water, based on the total weight of the etchant.
 2. Themethod of claim 1, wherein the lower gate metal layer and the lower datametal layer are made of titanium or titanium-containing metal and theupper gate metal layer and the upper data metal layer are made of copperor copper-containing metal.
 3. The method of claim 2, wherein thepersulfate is selected from ammonium persulfate, sodium persulfate,potassium persulfate, or a combination comprising at least one of theforegoing.
 4. The method of claim 3, wherein the inorganic acid isselected from nitric acid, sulfuric acid, phosphoric acid, perchloricacid, or a combination comprising at least one of the foregoing, and theinorganic acid salt is selected from nitrate, sulfate, phosphate,perchlorate, or a combination comprising at least one of the foregoing.5. The method of claim 4, wherein the cyclic amine compound is selectedfrom 5-aminotetrazole, tolyltriazole, benzotriazole, methyltriazole, ora combination comprising at least one of the foregoing.
 6. The method ofclaim 5, wherein the organic acid is selected from acetic acid, glycolicacid, citric acid, oxalic acid, or a combination comprising at least oneof the foregoing, and the organic acid salt is selected from a potassiumsalt, a sodium salt, an ammonium salt, or a combination comprising atleast one of the foregoing of a compound selected from acetic acid,glycolic acid, citric acid, oxalic acid, or a combination comprising atleast one of the foregoing.
 7. The method of claim 6, wherein thefluoride-containing compound is selected from ammonium fluoride, sodiumfluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride,potassium bifluoride, or a combination comprising at least one of theforegoing.
 8. The method of claim 7, wherein the upper data metal layerand the lower data metal layer are etched using the copper-titaniumetchant at the same time.
 9. The method of claim 2, wherein the upperdata metal layer is etched using a copper etchant.
 10. The method ofclaim 9, wherein the copper etchant includes 5 to 20 wt % of persulfate,1 to 10 wt % of at least one compound of an inorganic acid, an inorganicacid salt, or a mixture comprising at least one of the foregoing, 0.3 to5 wt % of a cyclic amine compound, 1 to 10 wt % of at least one compoundof an organic acid, an organic acid salt, or a mixture comprising atleast one of the foregoing, 0.1 to 5 wt % of p-toluenesulfonic acid, andwater, based on the total weight of the etchant.